This invention relates to a method of making a composite ski which includes a molded ski body and a metal top. The invention finds particular utility in making water skis, and the invention will be explained in conjunction with the manufacture of water skis. However, it will be understood that the invention can also be used for making snow skis.
Composite water skis are conventionally made by wrapping fiberglass around a foam core, saturating the fiberglass with epoxy resin, and inserting the raw ski body into a mold. The mold is then closed and applies pressure and heat to cure the ski body. After a period of time, the ski body is removed from the mold and deflashed, and the top surface is sanded. Adhesive is applied to the top surface, and a metal ski top is aligned with the ski body and bonded thereto by the adhesive.
If the metal top could be bonded directly to the ski body during the molding cycle, the steps of sanding the molded ski body, applying adhesive, and aligning and fitting the top to the ski body could be eliminated. However, unsatisfactory results are obtained if the metal top is fixed to the top mold part at both ends or is merely positioned over the ski body as the mold closes. Ski tops and ski bodies have different rates of thermal expansion, and the ski top also generally has a different rate of thermal expansion than the mold. As a result, the top tends to wrinkle during the curing cycle as temperatures change. It is also desirable to maintain a certain spacing from the edge of the metal top to the edge of the ski body, e.g., 0.020 inch. This spacing preserves the flash line or clearance designed into the mold for escape of resin and prevents the metal top from expanding from the heat of the mold and sealing off the flash line and/or buckling or otherwise deforming the periphery of the top against the walls of the mold cavity during the compression molding cycle.